Tangential thread rolling head

ABSTRACT

The invention relates to a tangential thread rolling head comprising two fork-like rolling head arms each rotatably coupled with a thread roll by an axle. The thread rolls respectively engage with a pinion and can be pushed laterally into an assembled position into the rolling head arms before installation of axles, in which one of the axles can be pushed into a bearing bore hole of the thread rolls. The thread rolls and the pinions have interacting catches that are configured such that each of the thread rolls can only be pushed laterally into the assembled position in a single defined rotary position.

CROSS REFERENCE TO RELATED INVENTION

This application is based upon and claims priority to, under relevant sections of 35 U.S.C. §119, European Patent Application No. 16 156 538.7, filed Feb. 19, 2016, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The invention relates to a tangential thread rolling head comprising two fork-like rolling head arms Each thread roll is rotatably mounted on an axle, wherein the thread rolls respectively engage with a pinion positioned on one of the axles of a gear joining the thread rolls. The thread rolls can be pushed laterally into an assembly position into the rolling head arms before installation of the axles, in which respectively one of the axles can be pushed into a bearing bore hole of the thread rolls, wherein the thread rolls and the pinions have interacting catches. The catches of the thread rolls and the pinions are configured such that each of the thread rolls can only be pushed laterally into the assembly position in a single defined rotary position.

Such a tangential thread rolling head is known from the document EP 0 811 443 B1. This type of tangential thread rolling head has the advantage that its proper function is ensured through the suitable configuration of the interacting catches of thread rolls and pinions that each of the thread rolls can only be installed into the rolling head arms in a single defined rotary position. Proper functioning of the tangential thread rolling head is thus ensured. The tangential thread rolling head known from EP 0 811 443 B1 can have in particular rolling head arms that can be pivoted towards each other. On the other hand, tangential thread rolling heads with fixed rolling head arms that cannot be pivoted towards each other are also known. For example, SU 654338 A1 shows such a tangential thread rolling head.

The aforementioned tangential thread rolling head is configured such that each of the thread rolls can only be inserted into the rolling head arm in a single defined rotary position, however each thread roll can be inserted into either rolling head arms, however for the operation of the tangential thread rolling head, it is essential that each thread roll is inserted into the rolling head arm associated with it, otherwise a malfunction could occur. The thread rolls are thus designed differently so that the thread profile designed on its circumferential dimension has an offset dimension required for the processing of workpieces in the installed state. If the thread rolls are interchanged, the correct offset dimension is not present. Thus, damage occurs during the processing of a workpiece. The technician must thus make sure that each thread roll is inserted into the correct rolling head arm. In practice, the thread rolls and the rolling head arms are thus marked in a suitable manner in order to show the association. Overall effort is thus increased and there is risk of faulty assembly.

BRIEF SUMMARY OF THE INVENTION

Based on the explained state of the art, the object of the invention is to provide a tangential thread rolling head of the initially named type, with which faulty assembly of the thread rolls is prevented using a simpler method.

For a tangential thread rolling head of the initially named type, the invention solves the object in that the catches of the thread rolls and the pinions are configured such that each of the catches of the thread rolls can only interact with the catches of a single associated pinion in order to reach the assembly position.

The tangential thread rolling head according to the invention has, in a generally known manner, two rolling head arms, in each of which one thread roll is received. The rolling head arms can be releasably held r on a rolling head holder. However, they can also be configured as one piece with a rolling head holder. The tangential thread rolling head has two thread rolls, which are respectively rotatably mounted on an axle. The rotary axles of the thread rolls run parallel to each other. A pinion is arranged on each axle, for example mounted on each respective axle. In their assembled position, the thread rolls respectively engage laterally with one of the pinions. For this, catches of the thread rolls and catches of the pinions engage in each other. The pinions form part of a gear, in particular a synchronous gear, joining the two thread rolls. The catches of the thread rolls can be pushed laterally into the catches of the respectively associated pinion in order to reach the assembled position. In the assembled position, bearing bore holes of the thread rolls coincide with bearing bore holes of the pinions so that the rotary axles can be pushed into the pinions and the thread rolls.

A suitable design of the catches of thread rolls and pinions ensures that each of the thread rolls can only be pushed laterally into the assembled position in a single defined rotary position, as is generally known from EP 0 811 443 B1. This first ensures that the thread rolls each have the correct rotary position for later proper operation. Faulty assembly with respect to the rotary position is thus excluded.

Moreover, according to the invention, a unique paired association between the thread rolls and pinions is ensured. For this, the catches of the thread rolls and associated pinions for the two pairs of thread rolls and pinions are different. Each thread roll can thereby only reach the assembled position in the case of insertion into the rolling head arm with the “correct,” namely the associated, pinion. In contrast, if an attempt is made to insert the thread roll into the other rolling head arm, the assembled position cannot be reached. In particular, a blockade or respectively an abutting of the catches of the thread roll against the catches of the pinion occurs before the assembled position is reached. The user sees this and can correspondingly insert the thread roll into the other rolling head arm. A faulty assembly through insertion of the thread rolls in the wrong rolling head arm is thus prevented according to the invention. Complex markings of the rolling head arms and thread rolls, which are intended to prevent faulty assembly in the state of the art, can simultaneously be foregone.

According to one embodiment, the catches of the thread rolls and the catches of the pinions respectively associated with the thread rolls can be complementary to each other. The complementary design can be used in all embodiments explained below. Together, the catches of the thread rolls and the catches of the associated pinions can form a complete circle or respectively circular ring.

According to a further embodiment, the thread rolls can each have a pair of opposite-lying catches and/or the pinions can each have a pair of opposite-lying catches.

According to a further embodiment, the distance between at least two opposite-lying ends of the catches of the thread rolls are different for the two thread rolls. Both thread rolls thus have one or more than one catch, wherein respectively at least two catch ends lie opposite each other. The distance between these opposite-lying ends is different on one thread roll than the other thread roll. As already mentioned, this embodiment is possible both in the case of thread rolls that only have one catch as well as in the case of thread rolls that have more than one catch. For example, if the thread rolls each have a pair of catches, the respective distance between all opposite-lying ends of the catches can be different for the two thread rolls.

According to a further embodiment, two opposite-lying ends of the catches of the thread rolls can lie on two imaginary parallel lines. This embodiment is particularly simple to realize in terms of production, for example through milling. The distance between the two imaginary parallel lines can be different for the two thread rolls. The imaginary lines can run in the insertion direction of the thread rolls in the rolling head arm or respectively the pinion. In turn, this embodiment is possible both in the case of thread rolls that only have one catch as well as in the case of thread rolls that have more than one catch.

According to a further embodiment, two ends of the catches of the thread rolls can lie on a common imaginary line. The common imaginary line can run for example perpendicular to the insertion direction of the thread rolls in the rolling head arm or respectively as a pinion. This embodiment is in turn particularly simple to realize in terms of production, for example through milling. The common imaginary lines can in turn be spaced from each other in the assembled position of the two thread rolls. For example, the common lines for the two thread rolls can have a different distance from the middle axle of the thread rolls. Especially when the thread rolls each have a pair of catches, the ends of the catches named in this embodiment can be the two other ends of the catches than the ends named in the aforementioned embodiment, which lie on the two imaginary parallel lines.

According to a further embodiment, at least two opposite-lying ends of the catches of the thread rolls can lie on the sides of an acute angle. The acute angle can be different for the two thread rolls. This embodiment is generally known from EP 0 811 443 B1.

According to a further embodiment, the catches of the thread rolls can respectively form at least one stop surface, wherein the stop surfaces in the assembled position abut against the catches of the associated pinions. For example, in the prior art according to EP 0 811 443 B1, the problem is that the complementary acute angles of the catch ends of thread rolls and pinions cannot be designed to be exactly the same size due to unavoidable production tolerances. As a result, the catches of the pinions are designed slightly smaller than the corresponding acute-angled seat formed by the catches of the thread roll. The thread roll is thereby in turn pushed slightly too far into the pinion when pushed all the way in so that the axles of the thread roll and pinion are not exactly flush. In practice, it is then complicated to push the common rotary axle through the pinion and the thread roll. This problem is overcome in the aforementioned embodiment of the invention in that a stop is formed by a defined stop surface and, when reached, the axles or respectively bearing bore holes of the thread rolls and pinions are exactly flush with each other. The assembly of the common rotary axle is correspondingly simplified.

The stop surfaces can have for example a curved progression, for example a circularly curved progression. The stop surfaces can in that case be adjusted for the outer diameter of the associated pinion. A particularly simple self-centering is achieved in this manner. It would also be possible, for example, that the stop surfaces progress into the assembled position at least in sections diagonal to the insertion direction of the thread rolls.

Furthermore, the stop surfaces can also respectively be formed by a stop section connecting two opposite-lying catch sections of the thread rolls. In this embodiment, it is possible that each thread roll has only one catch. This catch has two opposite-lying catch sections, which are interconnected by the stop section. In contrast, the associated pinion can have two catches.

It can be provided according to a further embodiment that the stop sections each have a smaller thickness than the opposite-lying catch sections so that a seat delimited by the stop surface is formed between the opposite-lying catch sections for a complementarily designed catch of the associated pinion. A pocket-shaped seat is thus formed, delimited laterally by the ends of the opposite-lying catch sections. The floor of the seat is formed by the stop surface of the stop section. A catch of the respectively associated pinion is received in this pocket-shaped seat. According to a further embodiment, the seats of the two thread rolls can have different widths.

In general, all combinations of the aforementioned embodiments according to the invention with each other are possible, which permit the unique association of the thread rolls to the pinions according to the invention.

According to a further embodiment, the tangential thread rolling head can comprise a rolling head holder, on which the rolling head arms are pivotably mounted on a common axle running parallel to the roll axles, as well as adjusting means for adjusting the pivot position of the rolling head arms on the rolling head holder. Thread means for adjusting the distance between the thread roll axles can also be provided.

In another embodiment, the tangential thread rolling head has fixed rolling head arms. The rolling head arm holder and the rolling head arms can then be configured for example as one piece.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are explained in greater detail below based on figures. They show schematically in:

FIG. 1 illustrates a perspective view of an embodiment of a tangential thread rolling head,

FIG. 2 illustrates a perspective view of another embodiment of a tangential thread rolling head,

FIG. 3 illustrates a perspective view of an embodiment of a first thread roll of a tangential thread rolling head,

FIG. 4 illustrates a perspective view of an embodiment of a first pinion of a tangential thread rolling head,

FIG. 5 illustrates a perspective view of the pinion from FIG. 4 installed onto the thread roll from FIG. 3,

FIG. 6 illustrates a side plan view of the pinion from FIG. 4 installed onto the thread roll from FIG. 3,

FIG. 7 illustrates a sectional view of the embodiment of FIG. 6 along the line A-A,

FIG. 8 illustrates a top plan view of the first thread roll from FIG. 3,

FIG. 9 illustrates a top plan view of the first pinion from FIG. 4,

FIG. 10 illustrates a top plan view of an embodiment of a second thread roll of a tangential thread rolling head,

FIG. 11 illustrates a top plan view of an embodiment of a second pinion of a tangential thread rolling head,

FIG. 12 illustrates a top plan view of an embodiment of a first thread roll of a tangential thread rolling head,

FIG. 13 illustrates a top plan view of an embodiment of a first pinion of a tangential thread rolling head,

FIG. 14 illustrates a top plan view of an embodiment of a second thread roll of a tangential thread rolling head, and

FIG. 15 illustrates a top plan view of an embodiment of a second pinion of a tangential thread rolling head.

If not otherwise specified, the same reference numbers indicate the same objects in the figures.

DETAILED DESCRIPTION OF THE INVENTION

The tangential thread rolling head according to the invention shown in FIG. 1 comprises a rolling head arm holder 10, on which a first fork-like rolling head arm 12 and a second fork-like rolling head arm 14 are configured as a single fixed piece. In the first rolling head arm 12, a first thread roll 16 is rotatably mounted on an axle 18. In the second rolling head arm 14, a second thread roll 20 is also rotatably mounted on an axle 22. The axles 18, 22 run parallel to each other. The basic structure and the function of such a tangential thread rolling head are known and are thus not explained in greater detail.

FIG. 2 shows an alternative embodiment of a tangential thread rolling head according to the invention. This tangential thread rolling head also has two rolling head arms 12′, 14′, in which the first and second thread rolls 16′, 20′ are rotatably mounted on axles 18′, 22′, respectively. The axles 18′, 22′ run parallel to each other. In contrast to the tangential thread rolling head from FIG. 1, the rolling head arms 12′, 14′ in the tangential thread rolling head from FIG. 2 are pivotably mounted on a common axle 24′ running parallel to the roll axles 18′, 22′. Reference number 26′ shows an adjustable spring and thread means are shown (not in greater detail), via which the pivot of the rolling head arms 12′, 14′ can be adjusted. The design and function of such a tangential thread rolling head with pivotable rolling head arms is also generally know and is thus not explained in greater detail.

FIG. 3 shows a first thread roll 28, which can be used just like the thread rolls explained in greater detail below in the tangential thread rolling heads shown in FIGS. 1 and 2. The first thread roll 28 has a bearing bore hole 32 defined by a hollow-cylindrical projection 30 into which the rotary axle can be inserted in the assembled position in the tangential thread rolling head. Two opposite-lying catches 34, 36 are disposed on the end of the hollow-cylindrical projection 30. FIG. 4 shows a first pinion 38, which can engage with the first thread roll 28 shown in FIG. 3. The first pinion 38 is part of a synchronous gear joining the two thread rolls of the tangential thread rolling head. The first pinion 38 has a hollow-cylindrical basic shape and thus also forms a bearing bore hole 40 for insertion of the rotary axle. The first pinion 38 also has a hollow-cylindrical projection 42, on which two catches 44, 46 are formed, which are designed complementary to the catches 34, 36 of the first thread roll 28 shown in FIG. 3. The catches 34, 36 of the first thread roll 28 can thereby engage with the catches 44, 46 of the first pinion 38, as shown in FIGS. 5-7. The first thread roll 28 is pushed laterally into the respective rolling head arm and onto the first pinion 38 such that the catch 44 of the first pinion 38 reaches from the bottom side in FIG. 3 into the free space formed between the opposite-lying ends of the catches 34, 36 until the catch 46 hits the bottom side of the catches 34, 36 in FIG. 3. This will be explained in greater detail below based on different exemplary embodiments.

FIG. 8 shows the first thread roll 28 shown in FIG. 3, while FIG. 9 shows the first pinion 38 shown in FIG. 4. FIG. 10 shows a second thread roll 28′ to be used in the same tangential thread rolling head as the first thread roll 28 from FIG. 8. The second thread roll 28′ has a hollow-cylindrical projection 30′, which defines a seat bore hole 32′ for the rotary axle of the second thread roll 28′ and forms a pair of catches 34′, 36′. FIG. 11 shows the second pinion 38′ interacting in the assembled position with second thread roll 28′ from FIG. 10. This in turn has a hollow-cylindrical basic shape, which forms a seat bore hole 40′ for the rotary axle and has a pair of catches 44′, 46′.

It can be seen in FIG. 8 that two opposite-lying ends of the catches 34, 36 of the first thread roll 28 lie on two imaginary parallel lines 48, 50. Moreover, it can be seen that the two other ends of the catches 34, 36 lie on an imaginary common line 52. These ends form respectively a stop surface for the catch 46 of the first pinion 38 when the first thread roll 28 is pushed laterally onto the first pinion 38, in FIG. 9 from top to bottom. In that case, the catch 44 of the first pinion 38 reaches into the free space between the ends of the catches 34, 36 lying opposite each other and on the parallel-running lines 48, 50 and the catch 46 of the first pinion 38 abuts against the other ends of the catches 34, 36. This embodiment ensures that the thread roll can only be brought into the assembled position engaging with the pinion 38 in a single defined rotary position. The stop surfaces formed by the ends of the catches 34, 36 ensure that the bearing bore holes 32, 40 in the assembled position are exactly flush with each other for pushing in the rotary axle.

The second thread roll 28′ shown in FIG. 10 differs from the first thread roll 28 shown in FIG. 8 only in terms of the design of the catches 34′, 36′. The opposite-lying ends of the catches 34′, 36′ thus also lie on two imaginary parallel lines 48′, 50′. However, the distance between the imaginary lines 48′, 50′ is greater than the distance between the imaginary lines 48, 50 of the first thread roll 28 from FIG. 8. Furthermore, the other ends of the catches 34′, 36′ of the second thread roll 28′ shown in FIG. 10 also lie on an imaginary common line 52′. However, this imaginary common line 52′ deviates in the assembled position from the imaginary common line 52 of the first thread roll 28 from FIG. 8. In particular, the imaginary common lines 52 and 52′ are spaced differently from the middle axle running through the bearing bore hole 32 or respectively 32′. While the common line 52 of the thread roll 28 shown in FIG. 8 lies on the middle axle of the thread roll 28, the common line 52′ of the thread roll 28′ shown in FIG. 10 is spaced with respect to the middle axle, namely offset downwards in FIG. 10. The second pinion 38′ shown in FIG. 11 has in turn catches 44′, 46′ designed complementary to the catches 34′, 36′. The function for pushing the second thread roll 28′ onto the second pinion 38′ is the same as explained above for FIGS. 8 and 9. The differently designed catches thereby ensure that the first thread roll 28 from FIG. 8 is uniquely associated with the first pinion 38 from FIG. 9 and that the second thread roll 28′ from FIG. 10 is uniquely assigned to the second pinion 38′ from FIG. 11. An assuming of the assembled position by combining the first thread roll 28 with the second pinion 38′ is just as impossible as by combining the second thread roll 28′ with the first pinion 38.

FIGS. 12-15 show another exemplary embodiment of first and second thread rolls insertable into the tangential thread rolling heads in FIGS. 1 and 2 or respectively associated first and second pinions. FIG. 12 shows a first thread roll 128, which in turn has a hollow-cylindrical projection 130 forming a bearing bore hole 132 for the rotary axle. The first thread roll 128 shown in FIG. 12 differs from the first thread roll 28 shown in FIG. 8 in terms of the design of the catches. Thus, the first thread roll 128 has only one catch 134. This catch 134 has a first catch section 135 and a second catch section 137. The two catch sections 135, 137 are interconnected by a stop section 139. The stop section 139 has a smaller thickness than the catch sections 135, 137 so that a seat 141 is formed by the stop section 139 and the catch sections 135, 137. The seat 141 has a width 143. The opposite-lying ends of the catch sections 135, 137 lie respectively on the sides of an acute angle 145.

The first pinion 138 shown in FIG. 13 has in turn a hollow-cylindrical basic shape, which forms a bearing bore hole 140 for the rotary axle. Furthermore, the pinion 138 has two catches 144, 146. The catches 144, 146 are complementary to the catch 134 of the first thread roll 128 from FIG. 12. In particular, the first thread roll 128 can be pushed laterally onto the first pinion 138 such that the catch 144 is received in the seat 141 of the first thread roll 128 and abuts against the stop surface 147 formed by the stop section 139. The catch 146 with its ends thereby comes to lie against the opposite-lying ends of the catch sections 135, 137. In this state, the bearing bore holes 132, 140 are flush with each other and it is ensured that the first thread roll 128 can only be pushed onto the first pinion 138 in a single rotary position.

FIG. 14 shows a second thread roll 128′, which can be inserted together with the first thread roll 128 into the tangential thread rolling head. In turn, the second thread roll 128′ has a hollow-cylindrical projection 130′, which forms a bearing bore hole 132′ for inserting the rotary axle. A catch 134′ comprises two catch sections 135′, 137′, which are interconnected by a stop section 139′, which in turn forms a seat 141′ and a stop surface 147′. In turn, the opposite-lying ends of the catch sections 135′, 137 lie on the sides of an acute angle 145′ and the seat 141′ has a width 143′. The second thread roll 128′ shown in FIG. 14 differs from the first thread roll 128 shown in FIG. 12 only in terms of the design of the catch 134′. Thus, the seat 141′ has on one hand a greater width 143′ than the seat 141 of the first thread roll 128 and the acute angle 145′ in the second thread roll 128′ is smaller than in the first thread roll 128.

The second pinion 138′ shown in FIG. 15 forms, in turn, a bearing bore hole 140′ for the rotary axle and has two catches 144′ and 146′, which are complementary to the catch 134′ of the second thread roll 128′. In the same manner as explained above for FIGS. 12 and 13, the second thread roll 128′ can be pushed onto the second pinion 138′.

The design of the catches 134 and 134′ ensures that the first thread roll 128 can only be brought into the assembled position in an interacting manner with the first pinion 138, and the second thread roll 128′ can only be brought into the assembled position in an interacting manner with the second pinion 138′.

REFERENCE LIST

-   10 Rolling head arm holder -   12 First rolling head arm -   12′ First rolling head arm -   14 Second rolling head arm -   14′ Second rolling head arm -   16 First thread roll -   16′ First thread roll -   18 Axle -   18′ Axle -   20 Second thread roll -   20′ Second thread roll -   22 Axle -   22′ Axle -   24′ Axle -   26′ Adjustable spring -   28 First thread roll -   28′ Second thread roll -   30 Hollow-cylindrical projection -   30′ Hollow-cylindrical projection -   32 Bearing bore hole -   32′ Bearing bore hole -   34 Catch -   34′ Catch -   36 Catch -   36′ Catch -   38 First pinion -   38′ Second pinion -   40 Bearing bore hole -   40′ Bearing bore hole -   42 Hollow-cylindrical projection -   44 Catch -   44′ Catch -   46 Catch -   46′ Catch -   48 Imaginary line -   48′ Imaginary line -   50 Imaginary line -   50′ Imaginary line -   52 Imaginary line -   52′ Imaginary line -   128 First thread roll -   128′ Second thread roll -   130 Hollow-cylindrical projection -   130′ Hollow-cylindrical projection -   132 Bearing bore hole -   132′ Bearing bore hole -   134 Catch -   134′ Catch -   135 First catch section -   135′ First catch section -   137 Second catch section -   137′ Second catch section -   139 Stop section -   141 Seat -   141′ Seat -   143 Width -   143′ Width -   144 Catch -   144′ Catch -   145 Acute angle -   145′ Acute angle -   146 Catch -   146′ Catch -   147 Stop surface -   147′ Stop surface 

1. A tangential thread rolling head comprising: two fork-like rolling head arms; two thread rolls, each having a bearing bore hole and one or more catches, each thread roll is rotatably mounted on an axle to the two fork-like rolling head arms, the two thread rolls are configured to be laterally pushed into an assembled position on the two fork-like rolling head arms before installation of each axle, each axle configured to be inserted into the bearing bore hole of one of the two thread rolls; and two pinions having one or more catches, wherein each of the two pinions is configured to engage a corresponding thread roll, wherein the catches of the thread rolls and the pinions are configured to interact with each other such that each of the thread rolls can only be pushed laterally into the assembled position in a single defined rotary position, and wherein the catches of the thread rolls are configured such that each of the catches of the two pinions can only interact with the catches of the corresponding thread roll.
 2. The tangential thread rolling head according to claim 1, wherein the one or more catches of the two pinons are complimentary to the catches of a respective corresponding thread roll.
 3. The tangential thread rolling head according to claim 1, wherein the catches on the thread rolls are disposed opposite each other and the catches on the pinions are disposed opposite each other.
 4. The tangential thread rolling head according to claim 3, wherein a distance between at least two oppositely disposed catches of one of the two thread rolls is different than at least two oppositely disposed catches of another thread roll.
 5. The tangential thread rolling head according to claim 3, wherein oppositely disposed ends of the oppositely disposed catches of the two thread rolls lie on two imaginary parallel lines.
 6. The tangential thread rolling head according to claim 5, wherein a distance between the two imaginary parallel lines for each of the two thread rolls is different.
 7. The tangential thread rolling head according to claim 3, wherein oppositely disposed ends of the catches of the thread rolls each lie on an imaginary common line.
 8. The tangential thread rolling head according to claim 7, wherein the imaginary common lines are spaced from each other when the two thread rolls are in the assembled position.
 9. The tangential thread rolling head according to claim 5, wherein at least two oppositely disposed ends of the catches of the two thread rolls lie on sides of an acute angle.
 10. The tangential thread rolling head according to claim 9, wherein the acute angle for each of the two thread rolls is different.
 11. The tangential thread rolling head according to claim 1, wherein the catches of the two thread rolls each form at least one stop surface configured to abut the catches of a corresponding pinion when in the assembled position.
 12. The tangential thread rolling head according to claim 11, wherein the at least one stop surface has a curved progression.
 13. The tangential thread rolling head according to claim 11, wherein the at least one stop surface is formed by a stop section connecting two opposite-lying catch sections of one of the two thread rolls.
 14. The tangential thread rolling head according to claim 13, wherein the stop section has a smaller thickness than the opposite-lying catch sections so that a seat delimited by the stop surface is formed between the opposite-lying catch sections for a complementarily designed catch of the corresponding pinion.
 15. The tangential thread rolling head according to claim 14, wherein the seat of each of the two thread rolls have different widths.
 16. The tangential thread rolling head according to claim 1, further comprising: a rolling head holder configured to pivotably mount the two fork-like rolling head arms on a common axle running parallel to a roll axles; and a means for adjusting a pivot position of the rolling head arms on the rolling head holder.
 17. The tangential thread rolling head according to claim 16, wherein the means for adjusting a pivot position of the rolling head arms on the rolling head holder comprises a spring. 